We had one at my old school who was 18, and looked all of 12. Scary thing was, he didn't even have his car driver's licence. His mum used to drop him off at work every morning. He was trying to grow a goatee to make himself look a bit older but he couldn't even do a decent job of that. Not surprisingly he found it difficult to persuade students to take him seriously let alone fly with him, I think he gave it up after a year or so.